Polish Pivotal GemFire starter and sample

Closes gh-5439

spring-boot-samples/spring-boot-sample-data-gemfire/src/main/java/sample/data/gemfire/config/SampleDataGemFireApplicationProperties.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright 2010-2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package sample.data.gemfire.config;
+
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.util.StringUtils;
+
+/**
+ * The SampleDataGemFireApplicationProperties class...
+ *
+ * @author John Blum
+ * @since 1.0.0
+ */
+@ConfigurationProperties(prefix = "sample.data.gemfire")
+public class SampleDataGemFireApplicationProperties {
+
+	protected static final String DEFAULT_LOG_LEVEL = "config";
+
+	private String logLevel = DEFAULT_LOG_LEVEL;
+
+	protected String defaultIfEmpty(String value, String defaultValue) {
+		return (StringUtils.hasText(value) ? value : defaultValue);
+	}
+
+	public String getLogLevel() {
+		return defaultIfEmpty(this.logLevel, DEFAULT_LOG_LEVEL);
+	}
+
+	public void setLogLevel(String logLevel) {
+		this.logLevel = logLevel;
+	}
+
+}